The Western Sand & Gravel site consists of about 25 acres of land, and is located in a rural area on the boundary of Burrillville and North Smithfield, Rhode Island. The site was a sand and gravel quarry operation from 1953 until 1975. From 1975 to 1979, approximately 12 acres of the 20-acre site were used for the disposal of liquid wastes, including chemicals and septic waste. Over time, the wastes penetrated into the permeable soil and contaminated the groundwater. Contents of tank trucks were also emptied directly into 12 open lagoons and pits, none of which were lined with protective materials. The pits were concentrated on a hill that slopes towards Tarkiln Brook, which is used for recreational purposes and drains into the Slaterville Reservoir. The State closed the disposal operation because nearby residents complained of odors. Approximately 600 people within a 1-mile radius of the site depended on groundwater and eight homes were historically found to have contaminated wells. All of these residences are now connected to a permanent water supply.

Groundwater is contaminated with volatile organic compounds (VOCs) including toluene, trichloroethylene (TCE), trichloroethane, benzene, chlorobenzene, and dichloroethane. The soil also was contaminated with VOCs.

In early 1980, the State began to pump one lagoon dry to halt leachate movement. Approximately 60,000 gallons of liquid chemical and septic waste were removed for off-site disposal. A groundwater recirculation system was installed.

Water Line ROD - 1984

Between 1990-1992, EPA built a permanent alternate water supply to service approximately 56 parcels of land. The potentially responsible parties installed carbon canister filters as a temporary protective measure in all the homes in the affected area until the permanent water supply was operational.

Soil Capping ROD - 1985

In 1988, the parties potentially responsible for the contamination installed a 2-acre cap over the areas of contaminated soil and sludge and graded the site to promote run-off and drainage. The site was also fenced and the potentially responsible parties agreed to maintain the fence, cap, and site. All remedial construction activities were considered complete at that time.

Groundwater ROD - 1991

The potentially responsible parties conducted an investigation to determine the extent of contamination and to evaluate alternatives for cleanup of the off-site groundwater. The investigation was completed in early 1991. Based on this investigation, the EPA selected a remedy of cleanup of groundwater through natural attenuation. The progress of natural attenuation was evaluated by EPA every three years for the first nine years following the ROD and has continued every five years thereafter. If natural attenuation is not progressing at the expected rate, EPA may require the installation of a groundwater pump and treat system. At the present time, the site groundwater continues to be cleaned up through natural attenuation processes.

Enforcement Highlights

In 1987, approximately 45 potentially responsible parties (PRPs) entered into a Consent Decree with the EPA and the State to pay for past costs, build a cap, conduct an investigation to determine the nature and extent of contamination, and identify alternatives for cleanup of contaminated groundwater. The parties also agreed to pay the EPA for the cost of construction of the alternate water supply system installed between 1990-1992.
Pursuant to a 1992 Consent Decree, three PRPs are currently monitoring the natural attenuation groundwater remedy discussed above. In addition, 33 de minimis PRPs agreed to reimburse EPA for both past and future costs.

Construction of all cleanup activities is complete, including fencing, capping, and grading the contaminated areas of the Western Sand & Gravel site, installing an alternative water supply system, and installing and monitoring a groundwater monitoring network. Stabilizing the site and providing an alternate water supply system are keeping the site safe while natural attenuation processes clean the groundwater.

Three separate remedy decisions have been made for this site. The latest in April 1991, required an evaluation of natural attenuation of the contaminants in the groundwater every three years for the first nine years and every five years thereafter. All reviews of the data to date indicate that natural attenuation of the contaminants is taking place at close to or slightly greater than the predicted rates. The last Five Year Review (September 2013) found that the remedies continue to function as designed, that natural attenuation is progressing, and that there is no need to consider active remediation at this time. It concluded that the Site is protective of human health and the environment.

However, it identified a gap in the groundwater data that has been collected; namely, the lack of sampling for the chemical known as 1,4-dioxane. In October 2014, under EPA and RIDEM supervision, the PRPs initiated a sampling plan to determine: whether 1,4-dioxane is present at the site, if present, whether it is attributable to the site, and what impact, if present, will it have on the projected time-frame for natural attenuation to be achieved. Issues in locating a historical monitoring well that was decommissioned have delayed the submittal of a final report for the sampling plan. EPA and RIDEM are currently awaiting an interim report of the data collected so far.

In October 2001, a Prospective Purchaser Agreement between EPA-New England and Supreme Mid-Atlantic, Inc. (Supreme) was signed. The Prospective Purchaser Agreement grants a covenant not to sue to Supreme with respect to existing contamination at the Site. Supreme purchased the 25-acre site in 2001. Supreme constructed a truck body assembly plant on the site in 2003-2004. The development consists primarily of a 20,000 square feet assembly building and open space for truck parking. The truck body assembly plant is currently in operation and employs about 30 people.

Supreme Mid-Atlantic, Inc. has recently approached EPA with a conceptual plan to build a solar energy array on top of the fenced, landfill capped area and possibly other areas. EPA, RIDEM, and the PRPs are currently discussing this plan with Supreme Mid-Atlantic in order to ensure compatibility with the ongoing remedy.